noun a machine for generating electrical charge from the friction between a spinning disc and a metal plate

A device utilized to produce electric charges through induction. It consists of a dielectricdisk made of resin or hardrubber, and a metalplate with an insulating handle. The disk is charged by rubbing it with fur, and the plate is placed on said disk, which charges said plate by induction. Then, the plate is momentarily grounded, removing negative charge, which leaves the plate with an induced positive charge.